Toner

Abstract

The toner comprises a toner particle that comprises a binder resin-containing core particle and a thermosetting resin-containing shell on the surface of the core particle, wherein the binder resin includes at least one of (i) a vinyl resin and a polyester resin and (ii) a hybrid resin in which a vinyl resin and a polyester resin are bonded; the polyester resin comprises in a main chain thereof a cyclic structure, and the content of the polyester resin in the tetrahydrofuran-soluble matter of the toner is at least 51 mass%; the vinyl resin comprises a prescribed monomer unit; the thermosetting resin is at least one resin selected from melamine resins, urea resins, and oxazoline group-bearing vinyl resins; and the average circularity of the toner is in a prescribed range.

What is claimed is: 
     
         1 . A toner comprising a toner particle, the toner particle comprising 
 a core particle containing a binder resin, and   a shell containing a thermosetting resin on the surface of the core particle, wherein   the binder resin comprises at least one of the following (i) and (ii):
 (i) a vinyl resin and a polyester resin, 
 (ii) a hybrid resin in which a vinyl resin and a polyester resin are bonded; 
   the polyester resin comprises in a main chain thereof a cyclic structure;   a content of the polyester resin having the cyclic structure in a fraction having a molecular weight of at least 2000, as provided by fractionation by preparative GPC from the tetrahydrofuran-soluble matter of the toner, is at least 51 mass%;   the vinyl resin comprises a monomer unit represented by the following formula (1)                          where, in the formula (1), R 1  represents a hydrogen atom or methyl group, and R 2  represents a straight-chain alkyl group having 10 to 14 carbons;   the thermosetting resin is at least one resin selected from the group consisting of a melamine resin, an urea resin, and a vinyl resin having an oxazoline group; and   the toner has an average circularity of 0.920 to 0.965.   
     
     
         2 . The toner according to  claim 1 , wherein a content of the vinyl resin in the fraction having a molecular weight of at least 2000, as provided by fractionation by preparative GPC from the tetrahydrofuran-soluble matter of the toner, is 1 to 49 mass%. 
     
     
         3 . The toner according to  claim 1 , wherein a content of the monomer unit represented by formula (1) in the vinyl resin is 1.0 to 15.0 mass%. 
     
     
         4 . The toner according to  claim 1 , wherein the toner particle comprises at least one ester compound selected from the group consisting of ester compounds represented by the following formula (2), ester compounds represented by the following formula (3), and ester compounds represented by the following formula (4) 
       
         
           
           
               
               
           
         
       
       
         
           
           
               
               
           
         
       
       
         
           
           
               
               
           
         
       
        where, in the formulas (2), (3), and (4), R 31  and R 41  each independently represent an alkylene group having 2 to 8 carbons, and R 32 , R 33 , R 42 , R 43 , R 51 , and R 52  each independently represent a straight-chain alkyl group having 14 to 24 carbons. 
     
     
         5 . The toner according to  claim 4 , wherein, using SPm (J/cm 3 ) ½  for the SP value of the monomer unit represented by formula (1), and using SPw (J/cm 3 ) ½  for the SP value of the ester compound,
 SPm is 18.00 to 19.00, and 
 SPm and SPw satisfy the following formula (a): 
             SPm   −   SPw       ≤   1.50         
 . 
 
     
     
         6 . The toner according to  claim 1 , wherein the toner comprises the toner particle and a crosslinked resin fine particle. 
     
     
         7 . The toner according to  claim 6 , wherein the crosslinked resin fine particle is a fine particle of a styrene-acrylic resin crosslinked by a crosslinking agent. 
     
     
         8 . The toner according to  claim 1 , wherein 
 the polyester resin is an amorphous polyester resin;   the toner particle further comprises a crystalline polyester resin; and 
math sizing
 the crystalline polyester resin comprises a monomer unit represented by the following formula (A) and a monomer unit represented by the following formula (B) 
                     
                     
  where, in the formula (B), n represents an integer of 4 to 14.